diff --git a/src/Duration.zig b/src/Duration.zig
index 1627090..a513085 100644
--- a/src/Duration.zig
+++ b/src/Duration.zig
@@ -4,6 +4,31 @@ const temporal = @import("temporal.zig");
 
 const Duration = @This();
 
+pub const RoundingOptions = temporal.RoundingOptions;
+pub const ToStringOptions = temporal.ToStringRoundingOptions;
+pub const ToStringRoundingOptions = temporal.ToStringRoundingOptions;
+pub const Unit = temporal.Unit;
+pub const RoundingMode = temporal.RoundingMode;
+pub const Sign = temporal.Sign;
+pub const PartialDuration = abi.c.PartialDuration;
+/// Relative-to context for duration operations.
+pub const RelativeTo = extern struct {
+    plain_date: ?*abi.c.PlainDate,
+    zoned_date_time: ?*abi.c.ZonedDateTime,
+
+    fn toCApi(self: RelativeTo) abi.c.RelativeTo {
+        return .{
+            .date = self.plain_date,
+            .zoned = self.zoned_date_time,
+        };
+    }
+};
+/// Options for Duration.total() providing unit and relative-to context.
+pub const TotalOptions = struct {
+    unit: Unit,
+    relative_to: ?RelativeTo = null,
+};
+
 _inner: *abi.c.Duration,
 
 /// Construct a Duration from years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, and nanoseconds.
@@ -216,30 +241,7 @@ fn wrapDuration(res: anytype) !Duration {
     return .{ ._inner = ptr };
 }
 
-// --- Public helper types -----------------------------------------------------
-
-pub const PartialDuration = abi.c.PartialDuration;
-
-/// Relative-to context for duration operations.
-pub const RelativeTo = extern struct {
-    plain_date: ?*abi.c.PlainDate,
-    zoned_date_time: ?*abi.c.ZonedDateTime,
-
-    fn toCApi(self: RelativeTo) abi.c.RelativeTo {
-        return .{
-            .date = self.plain_date,
-            .zoned = self.zoned_date_time,
-        };
-    }
-};
-
-/// Options for Duration.total() providing unit and relative-to context.
-pub const TotalOptions = struct {
-    unit: Unit,
-    relative_to: ?RelativeTo = null,
-};
-
-// --- Public type aliases and enums ------------------------------------------
+// --- Aliases and enums ------------------------------------------
 
 const OptionU8 = abi.c.OptionU8;
 const OptionU32 = abi.c.OptionU32;
@@ -249,13 +251,6 @@ const Precision = abi.c.Precision;
 const Unit_option = abi.c.Unit_option;
 const RoundingMode_option = abi.c.RoundingMode_option;
 
-pub const RoundingOptions = temporal.RoundingOptions;
-pub const ToStringOptions = temporal.ToStringRoundingOptions;
-pub const ToStringRoundingOptions = temporal.ToStringRoundingOptions;
-pub const Unit = temporal.Unit;
-pub const RoundingMode = temporal.RoundingMode;
-pub const Sign = temporal.Sign;
-
 // --- Tests -------------------------------------------------------------------
 
 test init {
diff --git a/src/Instant.zig b/src/Instant.zig
index b58b31e..d588802 100644
--- a/src/Instant.zig
+++ b/src/Instant.zig
@@ -3,17 +3,39 @@ const abi = @import("abi.zig");
 const temporal = @import("temporal.zig");
 
 const Duration = @import("Duration.zig");
-const Instant = @This();
 
-_inner: *abi.c.Instant,
-epoch_milliseconds: i64,
-epoch_nanoseconds: i128,
+const Instant = @This();
 
 pub const Unit = temporal.Unit;
 pub const RoundingMode = temporal.RoundingMode;
 pub const Sign = temporal.Sign;
 pub const RoundingOptions = temporal.RoundingOptions;
 pub const DifferenceSettings = temporal.DifferenceSettings;
+/// Options for Instant.toString()
+/// See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal/Instant/toString
+pub const ToStringOptions = struct {
+    /// Either an integer from 0 to 9, or null for "auto".
+    /// If null (auto), trailing zeros are removed from the fractional seconds.
+    /// Otherwise, the fractional part contains this many digits, padded with zeros or rounded as necessary.
+    fractional_second_digits: ?u8 = null,
+
+    /// Specifies how to round off fractional second digits beyond fractionalSecondDigits.
+    /// Defaults to "trunc" (truncate).
+    rounding_mode: ?RoundingMode = null,
+
+    /// Specifies the smallest unit to include in the output.
+    /// Possible values: "minute", "second", "millisecond", "microsecond", "nanosecond".
+    /// If specified, fractional_second_digits is ignored.
+    smallest_unit: ?Unit = null,
+
+    /// Time zone to use. Either a time zone identifier string or null for UTC.
+    /// Note: In the Zig API, this must be pre-resolved to a TimeZone struct.
+    time_zone: ?abi.c.TimeZone = null,
+};
+
+_inner: *abi.c.Instant,
+epoch_milliseconds: i64,
+epoch_nanoseconds: i128,
 
 /// Construct from epoch nanoseconds (Temporal.Instant.fromEpochNanoseconds).
 pub fn init(epoch_ns: i128) !Instant {
@@ -215,29 +237,7 @@ fn parseDuration(text: []const u8) !DurationHandle {
     return wrapDuration(abi.c.temporal_rs_Duration_from_utf8(view));
 }
 
-// --- Public helper types -----------------------------------------------------
-
-/// Options for Instant.toString()
-/// See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal/Instant/toString
-pub const ToStringOptions = struct {
-    /// Either an integer from 0 to 9, or null for "auto".
-    /// If null (auto), trailing zeros are removed from the fractional seconds.
-    /// Otherwise, the fractional part contains this many digits, padded with zeros or rounded as necessary.
-    fractional_second_digits: ?u8 = null,
-
-    /// Specifies how to round off fractional second digits beyond fractionalSecondDigits.
-    /// Defaults to "trunc" (truncate).
-    rounding_mode: ?RoundingMode = null,
-
-    /// Specifies the smallest unit to include in the output.
-    /// Possible values: "minute", "second", "millisecond", "microsecond", "nanosecond".
-    /// If specified, fractional_second_digits is ignored.
-    smallest_unit: ?Unit = null,
-
-    /// Time zone to use. Either a time zone identifier string or null for UTC.
-    /// Note: In the Zig API, this must be pre-resolved to a TimeZone struct.
-    time_zone: ?abi.c.TimeZone = null,
-};
+// --- Helper types -----------------------------------------------------
 
 const DurationHandle = struct {
     ptr: *abi.c.Duration,
diff --git a/src/Now.zig b/src/Now.zig
index d3f40d8..1001e0b 100644
--- a/src/Now.zig
+++ b/src/Now.zig
@@ -1,10 +1,11 @@
-const Now = @This();
 const Instant = @import("Instant.zig");
 const PlainDate = @import("PlainDate.zig");
 const PlainDateTime = @import("PlainDateTime.zig");
 const PlainTime = @import("PlainTime.zig");
 const ZonedDateTime = @import("ZonedDateTime.zig");
 
+const Now = @This();
+
 pub fn instant() error{Todo}!Instant {
     return error.Todo;
 }
@@ -29,7 +30,7 @@ pub fn zonedDateTimeISO() error{Todo}!ZonedDateTime {
     return error.Todo;
 }
 
-// --- Tests ---------------------
+// ---------- Tests ---------------------
 test instant {
     if (true) return error.Todo;
 }
diff --git a/src/PlainDate.zig b/src/PlainDate.zig
index 7fb3937..2430328 100644
--- a/src/PlainDate.zig
+++ b/src/PlainDate.zig
@@ -1,27 +1,29 @@
 const std = @import("std");
-const PlainDate = @This();
+
 const PlainDateTime = @import("PlainDateTime.zig");
 const PlainMonthDay = @import("PlainMonthDay.zig");
 const PlainYearMonth = @import("PlainYearMonth.zig");
 const ZonedDateTime = @import("ZonedDateTime.zig");
 const Duration = @import("Duration.zig");
 
-pub var calendarId: []const u8 = "";
-pub var day: i64 = 0;
-pub var dayOfWeek: i64 = 0;
-pub var dayOfYear: i64 = 0;
-pub var daysInMonth: i64 = 0;
-pub var daysInWeek: i64 = 0;
-pub var daysInYear: i64 = 0;
-pub var era: []const u8 = "";
-pub var eraYear: i64 = 0;
-pub var inLeapYear: bool = false;
-pub var month: i64 = 0;
-pub var monthCode: []const u8 = "";
-pub var monthsInYear: i64 = 0;
-pub var weekOfYear: i64 = 0;
-pub var year: i64 = 0;
-pub var yearOfWeek: i64 = 0;
+const PlainDate = @This();
+
+calendar_id: []const u8,
+day: i64 = 0,
+day_of_week: i64,
+day_of_year: i64,
+days_in_month: i64,
+days_in_week: i64,
+days_in_year: i64,
+era: []const u8,
+era_year: i64,
+in_leap_year: bool,
+month: i64,
+month_code: []const u8,
+months_in_year: i64,
+week_of_year: i64,
+year: i64,
+year_of_week: i64,
 
 pub fn init() error{Todo}!PlainDate {
     return error.Todo;
@@ -95,6 +97,7 @@ pub fn withCalendar() error{Todo}!PlainDate {
     return error.Todo;
 }
 
+// ---------- Tests ---------------------
 test compare {
     if (true) return error.Todo;
 }
diff --git a/src/PlainDateTime.zig b/src/PlainDateTime.zig
index 8379e33..cca9f27 100644
--- a/src/PlainDateTime.zig
+++ b/src/PlainDateTime.zig
@@ -1,32 +1,34 @@
 const std = @import("std");
-const PlainDateTime = @This();
+
 const PlainDate = @import("PlainDate.zig");
 const PlainTime = @import("PlainTime.zig");
 const ZonedDateTime = @import("ZonedDateTime.zig");
 const Duration = @import("Duration.zig");
 
-pub var calendarId: []const u8 = "";
-pub var day: i64 = 0;
-pub var dayOfWeek: i64 = 0;
-pub var dayOfYear: i64 = 0;
-pub var daysInMonth: i64 = 0;
-pub var daysInWeek: i64 = 0;
-pub var daysInYear: i64 = 0;
-pub var era: []const u8 = "";
-pub var eraYear: i64 = 0;
-pub var hour: i64 = 0;
-pub var inLeapYear: bool = false;
-pub var microsecond: i64 = 0;
-pub var millisecond: i64 = 0;
-pub var minute: i64 = 0;
-pub var month: i64 = 0;
-pub var monthCode: []const u8 = "";
-pub var monthsInYear: i64 = 0;
-pub var nanosecond: i64 = 0;
-pub var second: i64 = 0;
-pub var weekOfYear: i64 = 0;
-pub var year: i64 = 0;
-pub var yearOfWeek: i64 = 0;
+const PlainDateTime = @This();
+
+calendar_id: []const u8,
+day: i64,
+day_of_week: i64,
+day_of_year: i64,
+days_in_month: i64,
+days_in_week: i64,
+days_in_year: i64,
+era: []const u8,
+era_year: i64,
+hour: i64,
+in_leap_year: bool,
+microsecond: i64,
+millisecond: i64,
+minute: i64,
+month: i64,
+month_code: []const u8,
+months_in_year: i64,
+nanosecond: i64,
+second: i64,
+week_of_year: i64,
+year: i64,
+year_of_week: i64,
 
 pub fn init() error{Todo}!PlainDateTime {
     return error.Todo;
@@ -104,6 +106,7 @@ pub fn withPlainTime() error{Todo}!PlainDateTime {
     return error.Todo;
 }
 
+// ---------- Tests ---------------------
 test compare {
     if (true) return error.Todo;
 }
diff --git a/src/PlainMonthDay.zig b/src/PlainMonthDay.zig
index f9fce12..daf95ca 100644
--- a/src/PlainMonthDay.zig
+++ b/src/PlainMonthDay.zig
@@ -2,9 +2,9 @@ const std = @import("std");
 const PlainMonthDay = @This();
 const PlainDate = @import("PlainDate.zig");
 
-pub var calendarId: []const u8 = "";
-pub var day: i64 = 0;
-pub var monthCode: []const u8 = "";
+calendar_id: []const u8,
+day: i64,
+month_code: []const u8,
 
 pub fn init() error{Todo}!PlainMonthDay {
     return error.Todo;
@@ -42,6 +42,7 @@ pub fn with() error{Todo}!PlainMonthDay {
     return error.Todo;
 }
 
+// ---------- Tests ---------------------
 test from {
     if (true) return error.Todo;
 }
diff --git a/src/PlainTime.zig b/src/PlainTime.zig
index 37f4596..caa4468 100644
--- a/src/PlainTime.zig
+++ b/src/PlainTime.zig
@@ -2,12 +2,12 @@ const std = @import("std");
 const PlainTime = @This();
 const Duration = @import("Duration.zig");
 
-pub var hour: i64 = 0;
-pub var microsecond: i64 = 0;
-pub var millisecond: i64 = 0;
-pub var minute: i64 = 0;
-pub var nanosecond: i64 = 0;
-pub var second: i64 = 0;
+hour: i64,
+microsecond: i64,
+millisecond: i64,
+minute: i64,
+nanosecond: i64,
+second: i64,
 
 pub fn init() error{Todo}!PlainTime {
     return error.Todo;
@@ -65,6 +65,7 @@ pub fn with() error{Todo}!PlainTime {
     return error.Todo;
 }
 
+// ---------- Tests ---------------------
 test compare {
     if (true) return error.Todo;
 }
diff --git a/src/PlainYearMonth.zig b/src/PlainYearMonth.zig
index f636228..1cff0af 100644
--- a/src/PlainYearMonth.zig
+++ b/src/PlainYearMonth.zig
@@ -3,16 +3,16 @@ const PlainYearMonth = @This();
 const PlainDate = @import("PlainDate.zig");
 const Duration = @import("Duration.zig");
 
-pub var calendarId: []const u8 = "";
-pub var daysInMonth: i64 = 0;
-pub var daysInYear: i64 = 0;
-pub var era: []const u8 = "";
-pub var eraYear: i64 = 0;
-pub var inLeapYear: bool = false;
-pub var month: i64 = 0;
-pub var monthCode: []const u8 = "";
-pub var monthsInYear: i64 = 0;
-pub var year: i64 = 0;
+calendar_id: []const u8,
+days_in_month: i64,
+days_in_year: i64,
+era: []const u8,
+era_year: i64,
+in_leap_year: bool,
+month: i64,
+month_code: []const u8,
+months_in_year: i64,
+year: i64,
 
 pub fn init() error{Todo}!PlainYearMonth {
     return error.Todo;
@@ -70,6 +70,7 @@ pub fn with() error{Todo}!PlainYearMonth {
     return error.Todo;
 }
 
+// ---------- Tests ---------------------
 test compare {
     if (true) return error.Todo;
 }
diff --git a/src/ZonedDateTime.zig b/src/ZonedDateTime.zig
index 96d3e3a..4efda94 100644
--- a/src/ZonedDateTime.zig
+++ b/src/ZonedDateTime.zig
@@ -1,39 +1,41 @@
 const std = @import("std");
-const ZonedDateTime = @This();
+
 const Instant = @import("Instant.zig");
 const PlainDate = @import("PlainDate.zig");
 const PlainDateTime = @import("PlainDateTime.zig");
 const PlainTime = @import("PlainTime.zig");
 const Duration = @import("Duration.zig");
 
-pub var calendarId: []const u8 = "";
-pub var day: i64 = 0;
-pub var dayOfWeek: i64 = 0;
-pub var dayOfYear: i64 = 0;
-pub var daysInMonth: i64 = 0;
-pub var daysInWeek: i64 = 0;
-pub var daysInYear: i64 = 0;
-pub var epochMilliseconds: i64 = 0;
-pub var epochNanoseconds: i128 = 0;
-pub var era: []const u8 = "";
-pub var eraYear: i64 = 0;
-pub var hour: i64 = 0;
-pub var hoursInDay: i64 = 0;
-pub var inLeapYear: bool = false;
-pub var microsecond: i64 = 0;
-pub var millisecond: i64 = 0;
-pub var minute: i64 = 0;
-pub var month: i64 = 0;
-pub var monthCode: []const u8 = "";
-pub var monthsInYear: i64 = 0;
-pub var nanosecond: i64 = 0;
-pub var offset: []const u8 = "";
-pub var offsetNanoseconds: i64 = 0;
-pub var second: i64 = 0;
-pub var timeZoneId: []const u8 = "";
-pub var weekOfYear: i64 = 0;
-pub var year: i64 = 0;
-pub var yearOfWeek: i64 = 0;
+const ZonedDateTime = @This();
+
+calendar_id: []const u8,
+day: i64,
+day_of_week: i64,
+day_of_year: i64,
+days_in_month: i64,
+days_in_week: i64,
+days_in_year: i64,
+epoch_milliseconds: i64,
+epoch_nanoseconds: i128,
+era: []const u8,
+era_year: i64,
+hour: i64,
+hours_in_day: i64,
+in_leap_year: bool,
+microsecond: i64,
+millisecond: i64,
+minute: i64,
+month: i64,
+month_code: []const u8,
+months_in_year: i64,
+nanosecond: i64,
+offset: []const u8,
+offset_nanoseconds: i64,
+second: i64,
+time_zone_id: []const u8,
+week_of_year: i64,
+year: i64,
+year_of_week: i64,
 
 pub fn init() error{Todo}!ZonedDateTime {
     return error.Todo;
@@ -127,6 +129,7 @@ pub fn withTimeZone() error{Todo}!ZonedDateTime {
     return error.Todo;
 }
 
+// ---------- Tests ---------------------
 test compare {
     if (true) return error.Todo;
 }
diff --git a/src/root.zig b/src/root.zig
index 6293f27..44b503a 100644
--- a/src/root.zig
+++ b/src/root.zig
@@ -12,6 +12,7 @@ const Temporal = @This();
 
 test Temporal {
     const std = @import("std");
+    _ = @import("abi.zig");
 
     const expected_scopes = .{
         "Duration",